The present invention relates to an improved sound board assembly for an upright piano, and more particularly relates to a sound board assembly for an upright piano made up of reduced number of components and producible with reduced number of operational steps for lowering in production cost.
In the following description, the fore side of a component refers to the side of the component near the front side of an upright piano in which the component is built.
It is well known that a sound board is used for an upright piano in order to transmit vibration energy of strings widely over its entire area for generation of rich musical tones.
In construction of an upright piano, a sound board in a vertical position is attached to the fore side surface of a sound board support which is made up of a sound board base and a base frame. The sound board base and the base frame both have rectangular constructions each of which is made up of four side bar like members connected to each other at four corner junctions. Due to unavoidable work and connection errors, steps are liable to be developed at the corner junctions and presence of such steps hinders tight and close attachment of the sound board to the sound board base and the sound board base to the base frame. Removal of such steps at the corner junctions necessitates application of surface finish during production of the sound board assembly. This apparently connects to increase in number of operational steps in the production. Further, a sound board is usually provided on its rear side surface with a number of ribs which extend in a direction normal to the grain direction for total directional transmission of the string vibration energy. Conventionally, each rib terminates at edges of the sound board. So, for snag surface contact of the sound board to the sound board base, some recesses must be formed in the fore side surface of the sound board base in order to receive the projecting rib ends on the rear side surface of the sound board. Formation of such rib rests further increases the number of operational steps in the production.
At attachment of the sound board to the sound board support, it is desirable that their relative position can be adjusted somewhat. In the case of the above-described construction, rib ends projecting on the sound board are quite snugly received within rib rests formed in the sound board base, and there is no room for even a slight adjustment in position.